Asbestos fiber treatment



June 14, 1960 D. A. FEIGLEY, JR., ETAL 2,940,892

ASBESTOS FIBER TREATMENT Filed Sept. 3, 1957 DRAIN TIME (secouos) OI I4 4 6 8 IO l2 SOAPS/WT- DRY ASBESTOS DRAIN 'rme (secorws) INVENTOR DAVID A. FEIGLEY, JR Q 2 4 6 a |0 2 4 LEONARD N- RAY, JRV

7a HYDROGENATED DIMER ACID SOAP/WT.

DRY ASBESTOS ATTORNEY 2,940,892 Patented June 14, 1960 nice ASBESTOS FIBER TREATMENT David A. Feigley, In, and Leonard N. Ray, Jr., Lancaster, Pa., assignors to Armstrong Cork Company, Lancaster, Pa., a corporafion of Pennsylvania Filed Sept. 3, 1957, Ser. No. 681,860 23 Claims. (Cl. 162-145) This invention relates generally to fibrous sheets and more particularly to water-laid fibrous sheets. Still more particularly, the invention relates to fast-draining fibrous sheets containing chrysotile asbestos fibers, and to a process of making them.

In the past it has been very dilficult to form asbestos sheets of substantial thickness on typical papermaking machines such as Fourdriniers and ordinary cylinder machines. This has been true in view of the very slow drainage characteristics of asbestos slurries. Such characteristics may be improved by deposition on the asbestos fibers of sufiicient amounts of various kinds of rubber. However, where an asbestos sheet is desired with a very small amount of binder or without any binder at all on the fibers, the problem of slow drainage has been an insurmountable one. Additionally, it is often desirable to form sheets of mixtures of asbestos fibers with wood pulp, cotton linters, rag furnish, glass fibers, mineral wool fibers, and the like. Although the fibers to be mixed with the asbestos fibers might themselves possess excellent drainage characteristics, the mixture which includes asbestos fibers in a significant amount will have the poor drainage rates characteristic of asbestos fibers alone. Where the slurry is slow-draining, the resulting sheet after drainage is so Wet and weak that wet pressing is very difiicult; special equipment is needed to run at all. Hence, there is a definite need for a teaching relating to the improvement of the drainage characteristics of waterlaid sheets comprising chrysotile asbestos fibers.

It is the primary object of the present invention to present such an improvement. It is the further object of the present invention to present a fibrous product which includes chrysotile asbestos fibers therein, which product possesses those characteristics necessary to render it fastdraining. It is a further object of the present invention to supply a method by means of which strong, water-laid, fibrous sheets of fibers comprising asbestos fibers may be readily prepared at high speed on standard papermaking equipment.

These objects are accomplished in a surprisingly effective and straightforward manner. The invention contemplates a sheet which has been made by forming in water a slurry comprising chrysotile asbestos fibers. To the slurry is added in critical amounts a water-soluble, aliphatic, organic compound having at least carbon atoms therein. The compound must contain at least one carboxylic acid salt group. The compound may also have other reactive centers therein other than the carboxylic acid salt groups, and preferably contains olefinic groups, i.e., carbon-to-carbon double bonded unsaturation. The resulting treated slurry will be found to be fast-draining and suitable for the formation of a strong wet sheet. A sheet is then formed from the thus treated slurry in the usual manner.

It is known to treat bundles of asbestos fibers, particularly in rock form, with detergents and fatty acid soaps. Such treatment is set forth in US. 2,626,213Novak, issued January 20, 1953, and US. 2,652,325'Novak,

issued September 15, 1953. These two patents teach the treatment of bundles of asbestos fibers with massive quantities of detergents and soaps for the purpose of separating the minute fibers one from the other. The patents disclose the enormous increase in drainage time when asbestos fibers are treated according to the teach: ings of the patents.

It remains to the present description, however, to point out that certain compounds, and-most important of allcritica1 quantities of those compounds yield an effect precisely opposite from that taught by the abovedescribed patents.

The role played by use of critical amounts of the additives utilized by the present invention is best illustrated by reference to the drawings in which: V Fig. 1 illustrates the change in drainage rate of asbestos slurries of fixed consistency treated with increasing amounts of a monobasic carboxylic acid soap; and

Fig. 2 illustrates the change in drainage rate of asbestos slurries of fixed consistency treated with increasing amounts of a soluble hydrogenated dimerized carboxylic fatty acid soap.

Both figures illustrate the completely unobvious and unexpected discovery that asbestos fiber slurries treated as taught by the present invention undergo initially a sharply decreasing drainage time, passing through an early optimum drainage time, and swiftly rising to a value worse than that possessed by the untreated slurry.

It can readily be seen that the drainage times contemplated by the present description are so difierent in order of magnitude from those contemplated by the above described patents that the difference is one or" kind. This is emphasized by the fact that the change in drainage rate contemplated by the present invention is also in a direction opposite to that contemplated by the abovedescribed patents.

The material contemplated for treatment in accordance with the present invention is chrysotile asbestos in the form of fibers and minute particles. These fibers may be used alone, or as mixtures with other papermaking fibers, or as mixtures of asbestos fibers with cement such as Portland cement. The chrysotile asbestos fibers must always be present since the present invention is directed at improving the drainage characteristics of asbestos fibers whether they be alone or in admixture with other fibers or with cement.

The amount of asbestos fibers present in a mixture of dissimilar fibers will range from by weight chrysotile asbestos fibers on down to about 3% by Weight asbestos fibers, based on the total dry weight of fibers pres ent. The beneficial effects obtained from the use of asbestos fibers in mixtures of other fibers generally becomes insignificant when the amount 3% by weight asbestos fibers produces a mixture in which the efiect of the asbestos is generally lost. Thus, the

present invention contemplates sheets containing between about 3% and 100% by weight chrysotile asbestos fibers.

Where fibers other than asbestos are to be incorporated into the sheet, the characteristics of those other fibers are relatively insignificant when contrasted with the drainage characteristics of the asbestos fibers in the mixture. Cellulosic fibers such as wood pulp, cotton linters, rag

furnish, or noncellulosic fibers such as glass fibers, mineral wool, and any of the other paper-making fibers will all have their drainage times drastically increased when admixed with more than about 3% by weight asbestos fibers based on the total Weight of the fibers. The present invention is particularly concerned in one modification with the preparation of specialty papers which con:

tain chrysotile asbestos and sulfite pulp wherein the asof asbestos fibers to be used falls below about 3% by weight asbestos fibers. based on the total weight of the fibers used. Less than 5 wilFhe fpartieularl i enii u wnm r x s ,i ,s r for one "ruouth at-froo temperature, generally under coiiditious; Alteriiativelyf'theyju ayhe curedflfor 7 ye groups; firicludirig rtiusaturatedf'carboneto ngeit eam u t l vary q ins item bjugh"asbestos-cement "compositions r ay vary ilY i 1116, z a vlq t 6f @sfifi .in ivsmep pfes'ent; many of the compositions sonog am "by weight asbestos fiber ar d.60% by weight cement. This byth'e formation' in e "place. Where athick sheet is to heforrn t is custom;-

7 i 7 o-aidTiri retrievingthe water. from the asbestos-cemeh mryqusy creeperr a shorter series, for exami 2-4heurs at-m te teruperax? ql hw d j evi s at evat te re fqrfiei ghth t is its'is fi th; "Gertaiu'asbestosce entpr iie'ts' are manufac'tured wherein a"portion of the ceuier is r'eplaced withothermaterials, such'as quartz sarrd. f replacement does not affect the present -iri M207 7 V i V l '7 treatmeutbf"the"asbestos fibersin order "to reduce the drain 'ge irate pf;- all aqueous slurries contain: 'the r V normaHyslow=draining asbestos fibers.

ljhe foroainiglbffthe slurry of fibers 7' accomplished'by methodsknowu ih the heasbestosEfibersand-other fibers, 7 any; 'aire'taken uip iii water generally to 'a-cou sis'teucy mthe 'range 'of about 0.55%. *The s'lurry ge'neially be mechahicallyqefme'das in afb'eater, Jordan Since asbestos fibers 7 v silable 'to refineseparately the' asbestos fibers andauy cejfiul'osic' "fibjer'sfu sed; asbestos fib ers 'in'ay" cause; undue wear 'd'eroisionfon certain of the'ta'cklein the-mechani to firoduce ai'sheet haviiig 'thedesired properties;

ch'ai act iist'ic's oftheferifire slurryv 7 f 'walter soluble salts of org'anic', carbogiylic acids. As v further limitation,ihecompouuds ruust-eontaiu at least -10' carbonafoms ir thecarbon' chain of the-acid.

- Tfixdin-Pdundymust' 'contain at least -l0- carbon atoms asbestos-fi rs," 7 7 a a 7 Iheiiompounds-to be added arewvater soluble salts of More th the The carbon chain iuthe "conrboundginay TQOSSESS egeato e ae 'theymay be cured since thefp-re'ser t"iriventi ou isconceruedwith theanpne carboxylic acid group' may be breseht on Water-soluble organic acid salts having large numbers of carbon atoms are especially suitable 'inthepresent'invention. Such acids are best illustrated by the dimerized and trimerized fatty acids which are readily available in '5 commerce. These acids are prepared by the thermal polymerization of drying oil acids carried out in a pressure vessel in the presence-'ofewater' in the form of steam.

V The resultingcoggpositiQB g lsi allyrcontain 410 11 the average about 3%nionomer,'75% dimer, and 22% trimer. 110 Suchapreduct;is;knowmas;dimerizediiattysacids' andisvill have :an iodine value of approximately fiO andanraci'rl number of approximately 1 -90. 'The'dimerizedacid itself is essentially ga v 3ecarho ediearhoxylicwacid obtained by 'dimerization of the'linoleic acid of soya, cottonseed, corn, 5 and linseed oils ofkciomifierc'e. Theiprodiict is frequently referred to as" dilinoleic acid. This dimerized acid product may be purchased under the name "Empoi 1022. It is appamtt th t th dimerizesl a ids and the .trimerizfi aeigsjures iltingi Item the ahavedelscribed pr ssurized msssina 'he ta e hi her 0i1entra ed. as1det d- Tittie t e m' sa td'maylh ip rchase as uch. The trimer acid is a 54-ca'rbon acid and 60111535 apluel 'cf e h x li adsks oups- .As alf rt en a ia ion 0 1' h? siimem-nd ri ii a ids, residual unsatura io '25 iii itli' ar cnj ham may ihe'li is tedih h i cge a li The ihy rq ate'd diincr acid-maybe Purchased und e sh me fE y 302.0%; t e pred m na tly t aigh 0 353. 9 'llyms z d iattyr ac ds describe a n ats r td crm- I V r 1 .Ar ith r la s f acids whichmee s he fin tioao f ori garlic acids given earlier are thoselfoundin the various grades of wo'odrosin. Wood rosih contains asits spliiiy ingredient abietic .acid. Ihenexttmqst common r a c fi l ood r o nais n nabis c d Sma le 9 Qffi ydrq bie acid, t hydro bieti acid,

jti -ii m q ac a e -a es n ,i ag wi a min 1 mm f lihydr oahi tic a d-J ari us. rad s of wo odirosins also contain small amouutsjoi hydrocarbons nd s erol whichp av no role n. co troll ng e d a na 7 characteristics of chrysotile asbestos fibers but which do no harin when wood rosin is used soluble form.

'45 M any commercially available fatty acids and fatty acid soaps'meet the earlier descri dQdefigition offllQSe-cornpq lndsw iiqh c ol he d a n g ,chalta r fic bestos fibers, These soaps may heirrsolid r'liqui'd'iorm.

a general] 111e,: liquid soaps" are eharacteristic'df'the nsaulre jdihlghera ty are audschd o pssa ch e a urated fishe -fatty a i Asian exchi a qu; a i s a fia ty acid mixturekof 46%" y ,7 V V a v a a .55 the lbala ice being a gatural resin, As .anexampleofthe 7 These compounds' may -generallybe'defined-as ali-- V i ph V i V drainage characteristics. or asbestos; fibers are the maleic" acid or maleicfr anhydride adducts] Diels-Aldervreaction) v of any of the llHSfl-lUJflB-tfidfiQids described above as for exampl s slino e a i bolst r-ac d, dilinclei acid, and t l r landpq ymer d rosinia ids s V r V '65 'ltfwill be appreciated that all of'the above-described 7 om ound .m etiflteista di efinit bnof iphatic orga mpouadjh is l ast wflcarbonetoms, sa d' pou oma! hasten: ca boxyl s cidsl g pstatfi dlear ier, inyeutionmu t' Iii view of the size 'o'fniost of the rnplecules, theeom- P u ds a e not ene a l l s es lc- 'l y a eh wever, easily reuderedsoluble "byjreaction withpan alkaline material;such ,-asanmonimsodiurnfhydroxidg potassiumn constitute a pre'ierred embodiruent jthereof,particularly sample of such acids, theremay begiven NeU-FatAZIZ the compoun s seful in them -tent, b pou e ted l o .thei r ate se l form;

tassium, and even to some extent with alkaline earth metal compounds and organic amines. It must be emphasized that the compounds used in the present invention need not be very soluble to be operable. They are used in amounts much less than 0.1% by weight of the water, so easy solubility is not necessary. In the present specification and claims, it is contemplated that the defined organic carboxylic acids are rendered water-soluble where necessary by reaction of the acid with a solubilizing alkaline ingredient to form a salt. Thus, the compound to be used will be selected from the group consisting of water-soluble acids, water-soluble acid salts, and mixtures thereof.

The actual step of adding the organic acid salt to the asbestos-containing aqueous slurry is readily accomplished by simply physically adding the salt to the slurry. Preferably the salt will first be taken up in water to form an aqueous solution or suspension and the salt will be added in the form of that solution or suspension. Use of a solution aids in quick dispersion of the water-soluble acid throughout the slurry and hastens the reaction that takes place between the organic acid and the surface of the asbestos fiber.

The amount of organic acid to be used in the present invention is critical within a narrow range. It has been found that the addition of amounts of the organic acid greater than about 11% by weight based on the dry weight of the asbestos fibers causes a reversal of the dramatic improvement in drainage rate which is the essence of the present invention. Hence, as a practical matter, the amount of acid to be used-no matter what particular acid-will always be less than about 11% by weight based on the dry weight of the asbestos fibers. The precise amount less than this practical maximum will be determined to some extent by the particular organic acid salt used. Relative hardness of the Water can cause some variation in the amount. As described earlier, those organic acid salts within the definition of those which control the drainage characteristics of asbestos fibers and which possess more than one carboxylic acid group on very long carbon chains have a more pronounced efiect for the purpose intended than the monocarboxylic acid salts. Within these two extremes, varying degrees of activity will be encountered, depending on the precise number of carboxylic acid groups. The minimum amount of the salts to be added will run about 0.2% by weight based on the dry weight of the asbestos fibers; this is the amount at which the improved drainage rate becomes consistently noticeable. The preferred amount of the salt will generally be in the range of 3-8% by weight acid based on the dry weight of the fiber Once the organic acid has been added in the desired amount to the aqueous slurry comprising asbestos fibers, agitation will be carried out for a sufi'icient length of time to disperse the acid thoroughly throughout the slurry. This time generally runs about one to ten minutes. The temperature of the water, efiiciency of agitation, consistency of the slurry, and like factors will control the agitation time. As stated earlier, the water-soluble organic acid salt reacts with the surface of the asbestos fiber and, since the reaction is fairly rapid, agitation need not be prolonged. This will be particularly true where the organic acid is added in the form of a water solution so that no time need be wasted waiting for the acid to dissolve in the water of the slurry.

After the reaction of the organic acid with the surface of the asbestos fiber, the slurry is formed into a sheet of paper or felt or board on standard papermaking equipment as, for example, a Fourdrinier wire or cylinder machine.

Drainage time of the slurry will be found to have been drastically reduced by treatment with the organic acid salt. Depending on the particular acid chosen, drainage time may be reduced to as little as one tenth of that of the untreated asbestos fibers. As mentioned earlier, the

drainage timemay be controlled by selection of the ar:

ticular acid within the class of compounds defined which will produce the best drainage time in the formation of a particular sheet. Since the drainage time is reduced, 5 the sheet formed is dryer and stronger and thus may be handled through wet presses on the machine in accordance with usual technics.

It is apparent that the usual sizing agents such as starch, casein, and cellulose gums may be used in conjunction with the sheetmaking processes described herein. Sizing and other processing variables may be carried out after the fibers have been treated and before the treated slurry is passed to the wire, or once the sheet has been formed on the wire. Hence, papers and felts made by the present process find a wide range of utility as writing and wrapping papers, as backing for floor and wall coverings, as gasketing materials, and the like.

For certain purposes it may be desirable to precipitate synthetic rubber binder onto the asbestos fibers, or mixture of fibers, to strengthen the sheet. Small amounts, generally l5% by weight rubber based on the weight of the fibers, will usually suffice for this purpose. Mere addition of the'latex to the treated slurry followed by agitation will cause precipitation of this small amount of rubber onto the fibers. Where larger amounts of rubber are to be added, addition of a precipitating agent such as a solution of papermakers alum will speed and complete the precipitation. The synthetic rubbers which can be used are those used in beater saturation processes and include butadiene-styrene copolymers, butadiene-acrylonitn'le copolymers, polychloroprene, and the like.

The following examples illustrateseveral embodiments of the invention. All parts are by weight unless otherwise stated. 85

Example I Chrysotile asbestos (SD) was refined for 15 minutes at 1.5% consistency in a Valley beater. When parts of this refined asbestos was dispersed in 12,000 parts of water and formed into a sheet in a 12" x 12" Noble and Wood forming mold, the drainage time was 390 seconds. The resulting sheet after drainage was so weak and wet that wet pressing was extremely difficult.

The run was repeated save that various acids were added to the 40 parts of chrysotile asbestos fibers dispersed in the 12,000 parts of water prior to the forming of the 12" x 12" sheet. Each acid was added as a 16% solution in water to which suflicient potassium hydroxide had been added to render the solution slightly alkaline.

The following table illustrates the results:

Amount of Drain Run Organic Acid Organic Time in No. Acid Seconds Salt,

Parts 1 None None 390 2. N eO-Fat 4212-. 3 110 3 2 240 4 3 98 5 1.5 85 6 3 110 7 Myristic Acid--- 3 265 8 Decanoic Acid- 3 305 3 mp0 at ac 3 37 Brassldl cld 3 165 Emegs; 3020-5 (hydrogenated dimer 3 35 am 13 Emery 3055-5 (trimer acid) 1. 5 39 14 Phenyl Stearlc Acid (mixture 01' 9- an 3 47 IO-substituted) Nee-Fat 4212 is a mixture of oleic acid, 46%; linoleic acid, 39%; linolinic acid, 3%; and a resin, 12%. P & G Soap is a mixture of the sodium salts of stearic, oleic, and palmitic acids; it was added as such in water solution. In all rims except run 3 the water-soluble acid solution was prepared by dissolving parts of the 7 3,500 11mm; waterkwasqplaced 40, parts asbestos pound'is unsaturated.

amass 7 acid, 25-5 :parts KOH @4955 parts water. Sufficient .7 offlthis' solution was used to-give the amount'cof acids shown jfin theabw table.

ltbe which used oetanoic:

' 8-carbon acid, gavesnbstantially. no improvement: overf 5 ponndzis a saturated-pglycarbgxyiig acid.

the eontrol whichused nothing. 'However;:;mn 8, \which 7 used decanoic acid, a 1( )carbon a1cid', pi'ddneetl"better than-120% decrease in drainage time. V 1 a Exmxflell; r o

"Into 12;000 oartsnf water-was. persedaifl partsz-sulfiter pulp. The drainage time oftlxis slurry underzthemoindi: tionsoof Example Ir-was .29 seconds; the Ganadiau zgnam freeness: was 320 seconds.

.1 mm amp; t

ass-tag V asbestostfihers in water was treated with 29.44 part of Nee-Fat 4212 solubilizedias in fixampleL'theixl rainage time was :26 seconds .and the Canadian ireeness iwas 360.;

7 Exam l I I' fiber. .'Ihe r,esu1ting s1urr ywa eaten :for -15 m nut n '11 Valley laboratory beater. Portland cement in the V amount'of 40 parts was diapqrscdiin 500 parts water in-.a in B n e o thre min a th n dd s t t sbesto 's ur y ha ta m 'a estc ppme s wa then mu dinm .a 12'' xi tmqldtcia't eve o Draina i im s ifii -scemadsa above the' screen.

Av id n ca to" hat; des r b abo e as de" exc p tha the as sto fiber w r tre ted w t a 4 1 ti nl pa .(d y'ha i) o the po a si m al i hyd o ena ed sd c d 'CEQPP GO prior to the addition oftthecegnent slurry. The drainage m asT s cond I we cl'aimr t r f t '14- A m nded-she comp ing chrYs tilietssh W fibers hose rf c are reacted'wit b ut2-11% weight based on 'thedry" weight of the fibers of 'a wat r-h Soluble salt of .an al phatic ori an snmpopn ha n -t least carbon atoms, said: compound "being" selected ffOin 'the gioifificonsistfngiiffatti"acidsjjioiymeiiid fatty ,acids j rosinacids, polymerized rosin acids, the reactieniptoductiof an unsaturated organic acid anda compound selected from the 'group consisting of maieic acid andmzaleic anhydridqand mixtures thereof.

2'. Asheetaccordingto-cla m-1-whereinsaid c0mp0nn V is a polycarboxylicacidy a A sheet ptn wi daaizsaaan amjiaati carboxylic acid contains36.carbonatoms.

earboxylic acid contains-Heathen atoms.

"Portions of sulfite 121111: 7 were replaced asbestos to determine drainage l'aiesiqfr iu'inixtm- Following are them-emits: r

'20- chrysotile fibersinch jcomgri weight of the asbestos fibers,

80' acid and: maleic an,

7 iUNITED STAT ScPATBNT A sheet or gtoti am' fwh d11 9135? v t- 1953,

A he cqdi atoislalml he aid'i@9m-' 7 pound is asaturatedr H 9.1.15 sheet .-ac cording to c1 '7, 1 compnsipgge miatgre of asbestos fibersand c llulose fibers; said $9 tfipsx being present in an .amount'of BASS/Ya by weightoi the mixture.

'10 'IGJALsheet according to claim 1 ,co ngrisingla mixtuie of asbestos fibers;;and ce ment; ,said'asbestosfiber ing 'presentt'in an amount of by -weight e f-the ture. I a

1 :11.-A:shets m cli-ng its aim- 9 qemainss bo '15 f :by weigntiasbest s fibers; '7

-..binder:dep9site1on .thertreaeted 7 ashestosfibersvi j r a ,7 :13. The 0i .0 water a rslurry comprising ch rysotiieesbestgzs ing to said rSIUIIFY-EQWQdeIESQLQQIGgal of a1 organic'compound having at least 10 ca J & an amount of about 92-11% by weight based 9 sa d-c mp n 16d1fIQfllih83P consi n Q ism) 5 y merized fatty a ds m s s ol efizes si aside! h i' i action -n od s f -a unsatu a ed cream? a an accompoiindselected from the group consisting .of .rnal 'e ic m a s tfi t e :hu e i teds 7-; e

1 :-p sess a o d n (w c a m 1 whe ein sai mpqundreompnise a PQ i Qa zYIiQaQ SI- 163m: process according Zip fl pound tcempxise a y samra pm sss awmills t9 compcm isemfisizs a unsatsro I th tic ambb n nos ed thsssk -t ea s fibb sln s osic fibetsk aid asbestosifi e s 1 1 122 sai ' 9:. f-z i ea abou by ei h. besibthekdiififi weight of, thesfihetsmresent .1 2 v ric esss i site s im; "-W h ereingsaid 5.5-; n iipm zss -as ordine e sh m 3 w eiei fi d adde llco pon d" eompti e a xy -aads V 1 Re ime Qwdsnh m imit es Se t-15; 1953 at; es

y isle and'tmim lhe s f an 

1. A WATER-LAID SHEET COMPRISING CHRYSOTILE ASBESTOS FIBERS WHOSE SURFACES ARE REACTED WITH ABOUT 0.2-11% BY WEIGHT BASED ON THE DRY WEIGHT OF THE FIBERS OF A WATERSOLUBLE SALT OF AN ALIPHATIC ORGANIC COMPOUND BEING SELECTED LEAST 10 CARBON ATOMS, SAID COMPOUND BEING SELECTED FROM THE GROUP CONSISTING OF FATTY ACIDS, POLYMERIZED FATTY ACIDS, ROSIN ACIDS, POLYMERIZED ROSIN ACIDS, THE REACTION PRODUCT OF AN UNSATURATED ORGANIC ACID AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF MALEIC ACID AND MALEIC ANHYDRIDE, AND MIXTURE THEREOF. 